Field of the Disclosure
The present disclosure relates generally to calibration methods for reducing engine exhaust emissions, and more particularly, to calibration methods for improving catalyst performance in three-way catalyst (TWC) applications.
Background Information
Calibrations strategies that do not require additional equipment, for example, spark control and air to fuel ratio (AFR) control, amongst others, are desirable for improving catalyst performance. Improving catalyst light-off to meet the requirements of gas emissions levels, fuel consumption levels, and exhaust equipment size requires proper calibration of internal combustion engines. Within internal combustion engines, the production of pollutant emissions during combustion and the conversion of these emissions by a catalytic converter require both a very precisely adjusted air to fuel ratio as well as catalytic material compositions capable of providing a high level of conversion efficiency.
Calibration strategies have been developed for the automotive sector that improve performance of catalysts in effectively removing exhaust pollutants. These strategies are directed toward satisfying the combined requirements of (a) meeting standard emission requirements, (b) minimizing fuel consumption, and (c) minimizing system cost including catalyst size and loadings, amongst others.
Accordingly, stricter statutory regulations for pollutant emissions make it necessary to develop catalysts, including material compositions with low platinum group metals loadings, which can enable performance synergies to reduce the pollutant emissions to as low a level as possible during operation of the internal combustion engines. Further, the use of new catalyst materials in conjunction with improved calibration strategies can achieve improved performance levels in the reduction of nitrogen oxide, unburnt hydrocarbons, and carbon monoxide emissions.